Field
Embodiments of the present disclosure are directed to a micro X-ray tube.
Related Arts
Generally, a diagnostic X-ray system such as a CT (Computed Tomography) may have filter mounted therein. The filter may serve to reduce X-rays with low energies because such X-rays may be useless in an imaging process. Thus, the filter may serve to minimize X-ray exposure of a subject. Further, the filter may act to enable uniformity in X-ray emissions to improve an acquired image quality. In a conventional X-ray tube, X-rays may be emitted through a glass tube or beryllium window, and the x-rays may be filtered by a separate metal plate, for example, made of an aluminum material.
FIG. 1 is a conceptional view of a conventional triode-type field emission X-ray tube and a filter mounted therein. In FIG. 1, the X-ray tube includes a cathode 10, a gate electrode 20, an anode 30, and insulators 41, and 42. The tube is further equipped with a filter 50. The cathode 10 is provided with an emitter. The gate electrode 20 applies an electrical field to the emitter. The anode 30 accelerates emitted electron-beams which in turn, collide with a target 31, resulting in generations of X-rays. The X-rays passes and are filtered by the filter 50. The insulators 41 and 42 insulate the electrodes respectively.
Such a triode-type field emission X-ray tube may facilitate an X-ray radiation-amount adjustment via a separation between gate and anode voltages, where the gate voltage adjusts an electron-beam amount and the anode voltage establishes electron-beam energy.
However, in the micro X-ray tube as in FIG. 1, due to a high voltage applied to the anode, there may disadvantageously be generated an abnormal field emission at a joint 60 between the gate electrode 20 and the insulator 42.